Wireless inventory tracking for containers

ABSTRACT

A system and method for managing the contents of a medical storage container such as a tray that has a required inventory of medical articles. A Faraday cage enclosure is used to isolate, scan, and inventory the container. The container and each of the medical articles in the container have a respective RFID tag. A processor is programmed to retrieve the inventory list for the container based on its tag and compare the actual contents of the container according to their tags to the inventory list. Missing items and extra items are noted.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/877,242 filed May 18, 2020 now U.S. Pat. No. 11,456,066, which is acontinuation of U.S. application Ser. No. 16/278,653 filed Feb. 18, 2019now U.S. Pat. No. 10,658,078, which is a continuation of U.S.application Ser. No. 15/838,310, filed Dec. 11, 2017, now U.S. Pat. No.10,210,954, which is a continuation of U.S. application Ser. No.14/943,010, filed Nov. 16, 2015, now U.S. Pat. No. 9,842,189, which is acontinuation of U.S. application Ser. No. 14/214,284, filed Mar. 14,2014, now U.S. Pat. No. 9,189,769, which is a continuation-in-part ofU.S. application Ser. No. 13/776,613 filed Feb. 25, 2013, now U.S. Pat.No. 8,686,859, which is a continuation of U.S. application Ser. No.12/631,861, filed Dec. 7, 2009, now U.S. Pat. No. 8,384,545 andapplication Ser. No. 14/214,284 also claims the benefit of U.S.Provisional Application No. 61/800,803, filed Mar. 15, 2013. All of theabove documents are incorporated herein by reference.

BACKGROUND

The invention relates generally to the field of wireless identificationof medical articles in a healthcare setting, and more particularly, to asystem and method for managing the inventory of medical articlecontainers.

There are a number of ways of identifying and tracking articlesincluding visually, optically (bar coding, for example), magnetically,RFID, weighing, and others. Where an automatic system for tracking isdesired, RFID is a candidate since identification data may be obtainedwirelessly. RFID tags have decreased in cost, which has made them evenmore attractive for such an application.

Radio-frequency identification (“RFID”) is the use of electromagneticenergy (“EM energy”) to stimulate a responsive device (known as an RFID“tag” or transponder) to identify itself and in some cases, provideadditionally stored data. RFID tags typically include a semiconductordevice having a memory, circuitry, and one or more conductive tracesthat form an antenna. Typically, RFID tags act as transponders,providing information stored in the semiconductor device memory inresponse to an RF interrogation signal received from a reader, alsoreferred to as an interrogator. Some RFID tags include securitymeasures, such as passwords and/or encryption. Many RFID tags alsopermit information to be written or stored in the semiconductor memoryvia an RF signal.

RFID tags may be incorporated into or attached to articles to betracked. In some cases, the tag may be attached to the outside of anarticle with adhesive, tape, or other means and in other cases, the tagmay be inserted within the article, such as being included in thepackaging, located within the container of the article, or sewn into agarment. The RFID tags are manufactured with a unique identificationnumber which is typically a simple serial number of a few bytes with acheck digit attached. This identification number is incorporated intothe tag during manufacture. The user cannot alter thisserial/identification number and manufacturers guarantee that eachserial number is used only once. This configuration represents the lowcost end of the technology in that the RFID tag is read-only and itresponds to an interrogation signal only with its identification number.Typically, the tag continuously responds with its identification number.Data transmission to the tag is not possible. These tags are very lowcost and are produced in enormous quantities.

Such read-only RFID tags typically are permanently attached to anarticle to be tracked and, once attached, the serial number of the tagis associated with its host article in a computer database. For example,a particular type of medicine may be contained in hundreds or thousandsof small vials. Upon manufacture, or receipt of the vials at a healthcare institution, an RFID tag is attached to each vial. Each vial withits permanently attached RFID tag will be checked into the database ofthe health care institution upon receipt. The RFID identification numbermay be associated in the database with the type of medicine, size of thedose in the vial, and perhaps other information such as the expirationdate of the medicine. Thereafter, when the RFID tag of a vial isinterrogated and its identification number read, the database of thehealth care institution can match that identification number with itsstored data about the vial. The contents of the vial can then bedetermined as well as any other characteristics that have been stored inthe database. This system requires that the institution maintain acomprehensive database regarding the articles in inventory rather thanincorporating such data into an RFID tag.

An object of the tag is to associate it with an article throughout thearticle's life in a particular facility, such as a manufacturingfacility, a transport vehicle, a health care facility, a storage area,or other, so that the article may be located, identified, and tracked,as it is moved. For example, knowing where certain medical articlesreside at all times in a health care facility can greatly facilitatelocating needed medical supplies when emergencies arise. Similarly,tracking the articles through the facility can assist in generating moreefficient dispensing and inventory control systems as well as improvingwork flow in a facility. Additionally, expiration dates can be monitoredand those articles that are older and about to expire can be moved tothe front of the line for immediate dispensing. This results in betterinventory control and lowered costs.

Other RFID tags are writable and information about the article to whichthe RFID tag is attached can be programmed into the individual tag.While this can provide a distinct advantage when a facility's computerservers are unavailable, such tags cost more, depending on the size ofthe memory in the tag. Programming each one of the tags with informationcontained in the article to which they are attached involves furtherexpense.

RFID tags may be applied to containers or articles to be tracked by themanufacturer, the receiving party, or others. In some cases where amanufacturer applies the tags to the product, the manufacturer will alsosupply a respective database file that links the identification numberof each of the tags to the contents of each respective article. Thatmanufacturer supplied database can be distributed to the customer in theform of a file that may easily be imported into the customer's overalldatabase thereby saving the customer from the expense of creating thedatabase.

Many RFID tags used today are passive in that they do not have a batteryor other autonomous power supply and instead, must rely on theinterrogating energy provided by an RFID reader to provide power toactivate the tag. Passive RFID tags require an electromagnetic field ofenergy of a certain frequency range and certain minimum intensity inorder to achieve activation of the tag and transmission of its storeddata. Another choice is an active RFID tag; however, such tags requirean accompanying battery to provide power to activate the tag, thusincreasing the expense of the tag and making them undesirable for use ina large number of applications.

Depending on the requirements of the RFID tag application, such as thephysical size of the articles to be identified, their location, and theability to reach them easily, tags may need to be read from a shortdistance or a long distance by an RFID reader. Such distances may varyfrom a few centimeters to ten or more meters. Additionally, in the U.S.and in other countries, the frequency range within which such tags arepermitted to operate is limited. As an example, lower frequency bands,such as 125 KHz and 13.56 MHz, may be used for RFID tags in someapplications. At this frequency range, the electromagnetic energy isless affected by liquids and other dielectric materials, but suffersfrom the limitation of a short interrogating distance. At higherfrequency bands where RFID use is permitted, such as 915 MHz and 2.4GHz, the RFID tags can be interrogated at longer distances, but theyde-tune more rapidly as the material to which the tag is attachedvaries. It has also been found that at these higher frequencies, closelyspaced RFID tags will de-tune each other as the spacing between tags isdecreased.

There are a number of common situations where the RFID tags may belocated inside enclosures. Some of these enclosures may have entirely orpartially metal or metallized surfaces. Examples of enclosures includemetal enclosures (e.g., shipping containers), partial metal enclosures(e.g., vehicles such as airplanes, buses, trains, and ships that have ahousing made from a combination of metal and other materials), andnon-metal enclosures (e.g., warehouses and buildings made of wood).Examples of objects with RFID tags that may be located in theseenclosures include loose articles, packaged articles, parcels insidewarehouses, inventory articles inside buildings, various goods insideretail stores, and various portable articles (e.g., passengeridentification cards and tickets, baggage, cargo, individual life-savingequipment such as life jackets and masks) inside vehicles, etc.

The read range (i.e., the range of the interrogation and/or responsesignals) of RFID tags is limited. For example, some types of passiveRFID tags have a maximum range of about twelve meters, which may beattained only in ideal free space conditions with favorable antennaorientation. In a real situation, the observed tag range is often sixmeters or less. Therefore, some of the enclosures described above mayhave dimensions that far exceed the read range of an individual RFIDtag. Unless the RFID reader can be placed in close proximity to a targetRFID tag in such an enclosure, the tag will not be activated and read.Additionally, metal surfaces of the enclosures present a seriousobstacle for the RF signals that need to be exchanged between RFIDreaders and RFID tags, making RFID tags located behind those metalsurfaces difficult or impossible to detect.

In addition to the above, the detection range of the RFID systems istypically limited by signal strength to short ranges, frequently lessthan about thirty centimeters for 13.56 MHz systems. Therefore, portablereader units may need to be moved past a group of tagged items in orderto detect all the tagged items, particularly where the tagged items arestored in a space significantly greater than the detection range of astationary or fixed single reader antenna. Alternately, a large readerantenna with sufficient power and range to detect a larger number oftagged items may be used. However, such an antenna may be unwieldy andmay increase the range of the radiated power beyond allowable limits.Furthermore, these reader antennae are often located in stores or otherlocations where space is at a premium and it is expensive andinconvenient to use such large reader antennae. In another possiblesolution, multiple small antennae may be used but such a configurationmay be awkward to set up when space is at a premium and when wiring ispreferred or required to be hidden.

In the case of medical supplies and devices, it is desirable to developaccurate tracking, inventory control systems, and dispensing systems sothat RFID tagged devices and articles may be located quickly should theneed arise, and may be identified for other purposes, such as expirationdates. In the case of medical supply or dispensing cabinets used in ahealth care facility, a large number of medical devices and articles arelocated closely together, such as in a plurality of drawers. Cabinetssuch as these are typically made of metal, which can make the use of anexternal RFID system for identification of the stored articlesdifficult. In some cases, such cabinets are locked due to the presenceof narcotics or other medical articles or apparatus within them that aresubject to a high theft rate. Thus, manual identification of the cabinetcontents is difficult due to the need to control access.

Providing an internal RFID system in such a cabinet can pose challenges.Where internal articles can have random placement within the cabinet,the RFID system must be such that there are no “dead zones” that theRFID system is unable to reach. In general, dead zones are areas inwhich the level of coupling between an RFID reader antenna and an RFIDtag is not adequate for the system to perform a successful read of thetag. The existence of such dead zones may be caused by orientations inwhich the tag and the reader antennae are in orthogonal planes. Thus,articles placed in dead zones may not be detected thereby resulting ininaccurate tracking of tagged articles.

Often in the medical field, there is a need to read a large number oftags attached to articles in such an enclosure, and as mentioned above,such enclosures have limited access due to security reasons. Thephysical dimension of the enclosure may need to vary to accommodate alarge number of articles or articles of different sizes and shapes. Inorder to obtain an accurate identification and count of suchclosely-located medical articles or devices, a robust electromagneticenergy field must be provided at the appropriate frequency within theenclosure to surround all such stored articles and devices to be surethat their tags are all are activated and read. Such medical devices mayhave the RFID tags attached to the outside of their containers and maybe stored in various orientations with the RFID tag (and associatedantenna) pointed upwards, sideways, downward, or at some other angle ina random pattern.

Generating such a robust EM energy field is not an easy task. Where theenclosure has a size that is resonant at the frequency of operation, itcan be easier to generate a robust EM field since a resonant standingwave may be generated within the enclosure. However, in the RFID fieldthe usable frequencies of operation are strictly controlled and arelimited. It has been found that enclosures are desired for the storageof certain articles that do not have a resonant frequency that matchesone of the allowed RFID frequencies. Thus, a robust EM field must beestablished in another way.

Additionally, where EM energy is introduced to such an enclosure forreading the RFID tags within, efficient energy transfer is ofimportance. Under static conditions, the input or injection of EM energyinto an enclosure can be maximized with a simple impedance matchingcircuit positioned between the conductor delivering the energy and theenclosure. As is well known to those of skill in the art, such impedancematching circuits or devices maximize the power transfer to theenclosure while minimizing the reflections of power from the enclosure.Where the enclosure impedance changes due to the introduction or removalof articles to or from the enclosure, a static impedance matchingcircuit may not provide optimum energy transfer into the enclosure. Ifthe energy transfer and resulting RF field intensity within theenclosure were to fall below a threshold level, some or many of the tagson articles within the enclosure would not be activated to identifythemselves, leaving an ineffective inventory system.

It is a goal of many health care facilities to keep the use of EM energyto a minimum, or at least contained. The use of high-power readers tolocate and extract data from RFID tags is generally undesirable inhealth care facilities, although it may be acceptable in warehouses thatare sparsely populated with workers, or in aircraft cargo holds.Radiating a broad beam of EM energy at a large area, where that EMenergy may stray into adjacent, more sensitive areas, is undesirable.Efficiency in operating a reader to obtain the needed identificationinformation from tags is an objective. In many cases where RFID tags areread, hand-held readers are used. Such readers transmit a relativelywide beam of energy to reach all RFID tags in a particular location.While the end result of activating each tag and reading it may beaccomplished, the transmission of the energy is not controlled except bythe aim of the user. Additionally, this is a manual system that willrequire the services of one or more individuals, which can also beundesirable in facilities where staff is limited.

In a healthcare environment, there are many storage systems for keymedical articles that are used for different purposes. Some are openaccess storage systems. In most of these cases, and especially foremergency storage systems, they must be restocked upon use on a prioritybasis. Examples of such emergency storage systems are “crash carts,”“anesthesia carts,” and others. See FIG. 23 for an example of a crashcart 300. Such carts usually include wheels 302 so that they are mobileand may have multiple drawers 304 in which various medical articles arestored. An external handle 306 is provided to assist in handling thecart 300. Access to these carts must be immediate and unhindered, andcontrolled access is not required. Upon usage of any item in the cart,the cart must be fully inventoried for resupply. This takes asignificant amount of time to accomplish correctly. The need to havethese carts immediately available for use requires action from thepharmacy in a timely manner. Upon resupply, the carts are usually sealedand placed in strategic locations within the healthcare facility forimmediate access.

Another type of storage system is commonly known as a tray or code tray,and may have other names. The code is typically used to identify themedical purpose of the tray, such as a “code blue” tray to resuscitate aperson undergoing cardiac arrest. Such a tray may be formed ofnon-metallic material such as composites or plastics. The tray holds allof the medications, tools, and equipment that are expected to berequired to complete a medical procedure or to handle a particularmedical event.

A tray is typically laid out and displayed in an easily recognizablefashion. Color may be used also to assist in managing the inventory ofthe tray. This allows an assistant to retrieve the correct medication orinstrument without delay. In the event that a surgeon is looking for theoptimum tool or medication, a quick glance at the surgical tray willallow the identification of all available tools at his or her disposal.Labels are often placed on the tray also that specify what is in thepockets of the tray.

An example of such a medical “tray” is shown in FIG. 24 . The tray 320is a single layer and includes various pharmaceuticals 322 and othermedical articles, such as pre-loaded syringes 324 (epinephrine syringe,lidocaine syringe, and an atropine syringe). The entire tray is sealedwith clear plastic wrap 326 and an inventory list 328 is contained justunder the plastic seal so that it is visible and readable withoutbreaking the seal. The Required Inventory list in this case identifiesthe name of the tray, such as “Childbirth Tray,” lists the contents ofthe tray, and includes other information such as the first expirationdate of any of the articles contained in the tray. The RequiredInventory list may also contain a plan layout of the tray showing whicharticles should be stored where. It may have multiple pages or only asingle page.

The tray 320 has been prepared by a pharmacist at the pharmacy becauseit has prescription medications in it (oxytocin for example). TheRequired Inventory list may also include brand names as well as genericnames, and National Drug Codes (“NDCs”) or Universal Product Codes(“UPCs”) as part of the inventory. State regulations typically allow ahospital or other facility to define the contents of its trays, andtherefore they can be selected based on particular “community” standardsand requirements. State regulations, typically require that the hospitalhave specific procedures to ensure accuracy of tray contents. Suchprocedures include inventory and restocking procedures, as well asdetection of expired and recalled medical articles. In the example ofFIG. 24 , the tray is relatively small. However for other purposes, atray can be much larger with many more medical articles. Some trays mayinclude additional layers that include additional items not contained inthe top layer.

If the seal is broken, regardless of whether any of the contents wereremoved, an inventory will likely be required. Existing processesrequire that this be done manually. Each of the articles in the tray isexamined to determine if it is expired or recalled, and is comparedagainst the Required Inventory list to determine if it should be in thetray. The Required Inventory list is also referenced for checking thatall required articles are in the tray and that extra articles are not inthe tray. Once it has been restocked, the tray 320 is resealed 326 andmay be placed on the floor again for medical use. Such examination andrestocking can take significant amounts of time and if a pharmacist isrequired to perform some of the inventory process, that pharmacist willbe unavailable to perform other duties. In such a manual procedure,mistakes can be made. Thus, a need has been identified to provide a moreefficient and accurate system and method to restock such carts andtrays.

Crash carts and trays must be resupplied periodically to replace expiredor recalled items, and if a cart or a tray was actually used, to replaceconsumed articles. As mentioned, such processes are typically performedmanually at a significant cost in time. Missing key medical articles ina tray could be devastating in an emergency situation. Thereforeaccuracy in the resupply is mandatory. Often, trays that have articlesthat are just nearing expiration must be returned to the pharmacy forresupply in advance of expiration due to the time it takes to processthe tray. Any recalled articles must also be removed and substitutionsmade. It is also possible that items foreign to the crash cart or trayhave been added while they were in the field, and these foreign articlesmust be found and removed.

Unfortunately, the above procedures tend to suffer from significantshortcomings. For instance, manual inspections can result in errors ascan resupply. Creating records of what was done is also generally timeconsuming and error prone, all of which drive up the cost of creatingand resupplying the carts and trays. There has therefore been recognizeda need for improvement in managing such crash carts and trays.

Furthermore, under the current system, the pharmacy is unable to createindividualized carts for patients. For example, certain patients may beprovided a patient-specific cocktail of drugs (this may be a mixed vialor a combination of drugs). Because these are non-standard drugs or drugcombinations, a pharmacist has to double check a drug list or aprescription list when creating a cocktail drug or filling apersonalized cart with medical items.

Hence, those skilled in the art have recognized a need for an improvedreal-time inventory system for managing medical article containersystems. Additionally, a need has been recognized for performing sucharticle management with a more compact, self-contained wireless readersystem that reduces the space needed to inventory crash carts and trays.A further need has been recognized for confining the energy used forreading wireless medical article identification devices to a particulararea so that accuracy of identification is obtained. The presentinvention fulfills these needs and others.

SUMMARY OF THE INVENTION

Briefly and generally there is provided a system and a method to managethe inventories of medical article storage containers, including traysand crash carts. In a first aspect, there is provided a medicalcontainer re-supply system for reading a data carrier that is attachedto a medical container and a data carrier attached to a medical articlelocated in the storage container to manage the inventory of the storagecontainer, the data carrier being responsive to electromagnetic energy(EM) of a frequency f1 in response to which the data carrier providesidentification data, the system comprising a metallic enclosure havingan internal storage area, the metallic enclosure further havingelectrically conductive walls that completely surround the internalstorage area and any medical article with associated data carrier placedtherein, the enclosure having a natural frequency of resonance f2 whichis different from a frequency f1 and to which a data carrier that isresponsive to frequency f1 is not responsive, a probe disposed at ametallic wall of the metallic enclosure within the metallic enclosure,the probe configured to inject electromagnetic energy of a frequency f1into the metallic enclosure, wherein the position of the probe inrelation to the metallic walls of the metallic enclosure is selected sothat reflected EM of frequency f1 within the metallic enclosure is inphase at the probe position to thereby optimize power transfer atfrequency f1 into the enclosure, an active impedance matching circuitcoupled to the probe and configured to actively more closely matchimpedance of the probe to impedance of the metallic enclosure atfrequency f1, a storage container having a data carrier identifying thecontainer, the container being located within the internal storage areaof the metallic enclosure and containing a medical article with anassociated data carrier identifying that medical article, both datacarriers being responsive to EM at frequency f1 but not operationallyresponsive to frequency f2, a receiving antenna disposed within themetallic enclosure and configured to receive the identification dataprovided by the data carrier, a predetermined required inventory list ofmedical articles for the storage container, a non-volatile memory onwhich is stored the inventory list of the storage container, a processorprogrammed to receive the identification data of the storage containerand the identification data of the article in the storage container,locate the storage container inventory list in the memory through theidentification of the storage container, locate the details of themedical article in the storage container in the memory through theidentification data of the medical article, and compare the details ofthe medical article against the required inventory list of the storagecontainer to manage the inventory of the container.

In more detailed aspects, the processor is also configured to determineif the article in the storage container is expired through locating thedetails of the medical article, including its expiration date, from thememory, comparing that expiration date to the present date, andproviding a notice of expiration if the two dates match or if theexpiration date of the medical article preceded the present date. Thememory includes a database in which the details of recalled items arecontained, and the processor further being programmed to compare thedetails of the medical article in the storage container to the recalledarticle database on the memory, and if the comparison shows that themedical article is recalled, to provide an indication of such recallstatus.

In a method aspect in accordance with the invention, there is provided amethod of resupplying a medical container by reading a data carrier thatis attached to the medical container and a data carrier attached to amedical article located in the storage container to manage the inventoryof the storage container, the data carrier having a specified operationfrequency f₁ in response to which the data carrier providesidentification data, the medical container and medical article beinglocated within an internal storage area of a metallic enclosure, themetallic enclosure further having electrically conductive walls thatcompletely surround the internal storage area and any medical articlewith associated data carrier placed therein, the metallic enclosurehaving a natural frequency of resonance f₂ which is a frequency otherthan the specified operation frequency f₁ of the data carrier, themethod comprising positioning a storage container within the internalstorage area of the enclosure, the storage container having a datacarrier identifying the container, the container containing a medicalarticle with an associated data carrier identifying that medicalarticle, both data carriers being responsive to EM at frequency f1 butnot operationally responsive to frequency f2, injecting electromagnetic(“EM”) energy of a frequency f₁ into the metallic enclosure from alocation within the enclosure, the injecting location being selected inrelation to the metallic walls so that reflected energy of frequency f₁within the metallic enclosure is in phase at the location of injectionto thereby optimize power transfer of EM energy at frequency f₁ into theenclosure, actively matching an impedance associated with injecting theEM energy into the metallic enclosure to more closely match an impedanceof the metallic enclosure at frequency f₁, receiving identification dataprovided by a data carrier located within the internal storage area ofthe metallic enclosure by means of an antenna disposed within themetallic enclosure, storing a predetermined required inventory list ofthe storage container on a non-volatile memory, receiving theidentification data of the storage container and the identification dataof the article in the storage container by a processor, locating thestorage container inventory in the memory by the processor through theidentification of the storage container, locating the details of themedical article in the storage container by the processor in the memorythrough the identification data of the medical article, and comparingthe details of the medical article against the required inventory listof the storage container to manage the inventory of the container.

In more detailed aspects, the method further comprises determining bythe processor if the article in the storage container is expired throughlocating the details of the medical article, including its expirationdate, from the memory, comparing that expiration date to the presentdate, and providing a notice of expiration if the two dates match or ifthe expiration date of the medical article preceded the present date.Also included is the aspect of comparing the details of the medicalarticle in the storage container to a recalled article database on thememory, and if the comparison shows that the medical article isrecalled, providing an indication of such recall status about themedical article.

The features and advantages of the invention will be more readilyunderstood from the following detailed description that should be readin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a drawer that may be positioned withina medical dispensing cabinet, showing the storage of a plurality ofmedical articles randomly positioned in the drawer, each of thosearticles having an integral RFID tag oriented randomly;

FIG. 2 is a perspective view of a medication dispensing cabinet havingfive drawers, one of which is similar to the schematic view of FIG. 1 ,the cabinet also having an integral computer for controlling access tothe cabinet and performing inventory tracking by periodically readingany RFID tags placed on articles stored within the cabinet, and forreporting the identified articles to a remote computer;

FIG. 3 is a block and flow diagram showing an embodiment in which anRFID reader transmits activating EM energy into a drawer containing RFIDtags with a single transmitting antenna, receives the data output fromthe activated RFID tags with a single receiving antenna, a computercontrolling the transmission of activating energy and receiving the datafrom the activated RFID tags for processing;

FIG. 4 is a block and flow diagram similar to FIG. 3 showing anembodiment in which an RFID reader transmits activating EM energy into adrawer containing RFID tags with two transmitting antennae, receives thedata output from the activated RFID tags with three receiving antennae,and as in FIG. 3 , a computer controlling the transmission of activatingenergy and receiving the data from the activated RFID tags forprocessing;

FIG. 5 shows an enclosure with a single probe and a connector, the probebeing configured to inject EM energy into the enclosure and excite a TEmode;

FIG. 6 shows an enclosure with a single probe and a connector, the probebeing configured to inject EM energy into the enclosure and excite a TMmode;

FIG. 7 shows a plot of coupled power in an enclosure as a function offrequency for a resonant enclosure where F_(n) is the natural resonancefrequency of the enclosure;

FIG. 8 shows a plot of coupled power (ordinate axis) in an enclosure asa function of frequency (abscissa axis), where f_(f) is a forcedresonance frequency, or otherwise referred to as a frequency that is notequal to the resonant frequency of the enclosure, and f_(n) is thenatural resonant frequency of the enclosure, showing the establishmentof a robust field of coupled power in the enclosure at the f_(f)frequency;

FIG. 9 shows an enclosure with two probes each with a connector forinjecting EM energy into the enclosure, one probe being a TM probe andthe other being a TE probe;

FIG. 10 shows a probe, a connector, and an attenuator that is used toimprove the impedance match between the probe and the enclosure;

FIG. 11 shows a probe, a connector, and a passive matching circuit thatis used to improve the impedance match between the probe and enclosure;

FIG. 12 shows an active matching circuit connected between a probelocated in an enclosure and a transceiver, the active matching circuitcomprising a tunable capacitor, a dual-directional coupler, multiplepower sensors, and a comparator used to provide a closed-loop, variablematching circuit to improve the impedance match between the probe andthe enclosure;

FIG. 13 provides a side cross-sectional view of the cabinet of FIG. 2 atthe location of a drawer with the drawer removed for clarity, showingthe placement of two probe antennae in a “ceiling mount” configurationfor establishing a robust EM field in the drawer when it is in place inthe cabinet in the closed position;

FIG. 14 is a perspective view of the metallic enclosure showing theprobe configuration of FIG. 13 again showing the two probe antennae forestablishing a robust EM field in a drawer to be inserted;

FIG. 15 is a cutaway perspective side view of the metallic enclosure orframe in which are mounted the dual probe antennae of FIGS. 13 and 14with the drawer removed for clarity;

FIG. 16 is a frontal perspective view of the view of FIG. 14 with acutaway plastic drawer in place in the metallic enclosure and furthershowing the dual ceiling mount probe antennae protected by anelectromagnetically inert protective cover, and further showing coolingsystem components mounted at the back of the cabinet near the drawer'sback, the drawing also showing a partial view of a drawer slidemechanism for ease in sliding the drawer between open and closedpositions in the cabinet, the drawer front and rear panels having beencutaway in this view;

FIG. 17 is a frontal perspective view at the opposite angle from that ofFIG. 16 with the plastic drawer completely removed showing the dualceiling mount probe antennae protected by the EM inert protective covermounted to the metallic enclosure, and further showing the coolingsystem components of FIG. 16 mounted at the back of the cabinet as aspring loading feature to automatically push the drawer to the openposition when the drawer's latch is released, the figure also showing amounting rail for receiving the slid of the drawer;

FIG. 18 is a schematic view with measurements in inches of the placementof two TE₀₁ mode probes in the top surface of the enclosure shown inFIGS. 13-15 ;

FIG. 19 is a schematic view of the size and placement within the drawerof FIG. 16 of two microstrip or “patch” antennae and their microstripconductors disposed between respective antennae and the back of thedrawer at which they will be connected to SMA connectors in oneembodiment, for interconnection with other components;

FIG. 20 is diagram of field strength in an embodiment of an enclosurewith a probe placed in the enclosure at a position in accordance withthe diagram of FIG. 19 ;

FIG. 21 is a lower scale drawing of the field intensity diagram of FIG.20 showing a clearer view of the field intensity nearer the front andback walls of the enclosure; and

FIGS. 22A and 22B together present a block electrical and signal diagramfor a multiple-drawer medical cabinet, such as that shown in FIG. 2 ,showing the individual multiplexer switches, the single RFID scanner,and power control;

FIG. 23 is a perspective view of a hospital crash cart having aplurality drawers, each of which may contain a tray of organized medicalarticles or the drawer may contain loose articles. The crash cart may besupplied to support a particular use in a healthcare facility, such asthe intensive care unit, pediatrics, or other;

FIG. 24 is a top view of a sealed code tray showing the inventory listsealed with the medical articles of the tray. Labels have been used toadvise on the particular contents of pockets of the tray;

FIG. 25 is a block diagram of a scanning and inventory system inaccordance with aspects of the invention in which a code tray is placedwithin an enclosure for scanning data carriers contained on each medicalarticle in the tray, the scanning results compared to databases, and theresults of the scanning indicating what resupply efforts area needed forthe tray;

FIG. 26 is a perspective view of a scanning enclosure in accordance withaspects of the invention that may be conveniently carried to variouslocations in a healthcare facility to scan and inventory trays and othercontainers, the enclosure providing a robust electromagnetic fieldwithin its cavity to activate and read all RFID tags located therein;

FIG. 27 is a perspective view of a much larger enclosure for crash cartsthat also provides an electromagnetic field within to activate, detect,and read all RFID tags in the crash cart and provide theiridentifications;

FIG. 28 is a flow chart showing embodiments of methods to build amedical articles database, build a tray database, and scan and inventorya tray to determine what changes in the medical article contents of atray need to be made to bring the tray to the inventory level required;

FIG. 29 is a flow chart of an embodiment of a method for scanning atray, determining its contents, and indicating any changed needed tosupply the tray according to a predetermined inventory; also shown is amethod for scanning medical articles of the tray for expired andrecalled articles;

FIG. 30 shows a program feature in which the method of FIG. 29 may becontrolled to search for expired articles within a selected time period;

FIG. 31 shows a program feature in which a graphic may be displayedshowing the layout of a particular tray and showing a blinking indicator(asterisk in this case) that shows in which pocket a particular medicalarticle is or should be placed; and

FIG. 32 shows a program feature in which the results of scanning a trayare displayed with lists multiple categories of the contents, such asexpired, recalled, missing, and others.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now in more detail to the exemplary drawings for purposes ofillustrating embodiments of the invention, wherein like referencenumerals designate corresponding or like elements among the severalviews, there is shown in FIG. 1 a schematic representation of a partialenclosure 20 in which a plurality of medical articles 22 are stored,each with a respective RFID tag 24 that has a unique identificationnumber. The partial enclosure may comprise a drawer having a front 26, aleft side 28, a right side 30, a rear 32, and a bottom 34. Thesearticles are randomly distributed in the drawer with the RFID tagsfacing in various and random directions.

As used in regard to the embodiments herein, “reader” and “interrogator”refer to a device that excites an RFID tag and that may read orwrite/read. The data capture device is always referred to as a reader oran interrogator regardless of whether it can only read or is alsocapable of writing. A reader typically contains a radio frequency module(a transmitter and a receiver, sometimes referred to as a“transceiver”), a control unit and a coupling element (such as anantenna or antennae) to the RFID tag. Additionally, many readers includean interface for forwarding data elsewhere, such as an RS-232 interface.The reader, when transmitting, has an interrogation zone within which anRFID tag will be activated. When within the interrogation zone, the RFIDtag will draw its power from the electrical/magnetic field created inthe interrogation zone by the reader. In a sequential RFID system (SEQ),the interrogation field is switched off at regular intervals. The RFIDtag is programmed to recognize these “off” gaps and they are used by thetag to send data, such as the tag's unique identification number. Insome systems, the tag's data record contains a unique serial number thatis incorporated when the tag is manufactured and which cannot bechanged. This number may be associated in a database with a particulararticle when the tag is attached to that article. Thus, determining thelocation of the tag will then result in determining the location of thearticle to which it is attached. In other systems, the RFID tag maycontain more information about the article to which it is attached, suchas the name or identification of the article, its expiration date, itsdose, the patient name, and other information. The RFID tag may also bewritable so that it can be updated.

As used in regard to the embodiments herein, “tag” is meant to refer toan RFID transponder. Such tags typically have a coupling element, suchas an antenna, and an electronic microchip. The microchip includes datastorage, also referred to as memory.

FIG. 2 presents a representative medical dispensing cabinet 40comprising a plurality of movable drawers 42. In this embodiment, thereare five drawers that slide outwardly from the cabinet so that access isprovided to the contents of the drawers. FIG. 1 is a schematic diagramof a representative drawer that may be positioned within the cabinet ofFIG. 2 for sliding outward to provide access to the drawer's contentsand for sliding inward into the cabinet to secure the drawer's contents.The cabinet also comprises an integral computer 44 that may be used tocontrol access to the drawers and to generate data concerning access andcontents, and to communicate with other systems. In this embodiment, thecomputer generates data concerning the number and type of articles inthe drawers, the names of the patients for whom they have beenprescribed, the prescribed medications and their prescribedadministration dates and times, as well as other information. In asimpler system, the computer may simply receive unique identificationnumbers from stored articles and pass those identification numbers to aninventory control computer that has access to a database for matchingthe identification numbers to article descriptions.

Such a cabinet may be located at a nursing station on a particular floorof a health care institution and may contain the prescriptions for thepatients of that floor. As prescriptions are prepared for the patientsof that floor, they are delivered and placed into the cabinet 40. Theyare logged into the integral computer 44, which may notify the pharmacyof their receipt. A drawer may also contain non-prescription medicalsupplies or articles for dispensing to the patients as determined by thenursing staff. At the appropriate time, a nurse would access the drawerin which the medical articles are stored through the use of the computer44, remove a particular patient's prescriptions and any needednon-prescription articles, and then close the drawer so that it issecured. In order to access the cabinet, the nurse may need to providevarious information and may need a secure access code. The drawers 42may be locked or unlocked, as conditions require.

The computer 44 in some cases may be in communication with otherfacilities of the institution. For example, the computer 44 may notifythe pharmacy of the health care institution that a patient'sprescription has been removed from the cabinet for administration at aparticular day and time. The computer may also notify the financedepartment of the health care institution of the removal ofprescriptions and other medical articles for administration to aparticular patient. This medication may then be applied to the patient'saccount. Further, the computer 44 may communicate to administration forthe purpose of updating a patient's Medication Administration Record(MAR), or e-MAR. The medication cabinet 40 computer 44 may be wirelesslyconnected to other computers of the health care institution or may havea wired connection. The cabinet may be mounted on wheels and may bemoved about as needed or may be stationary and unable to move.

Systems that use RFID tags often employ an RFID reader in communicationwith one or more host computing systems that act as depositories tostore, process, and share data collected by the RFID reader. Turning nowto FIGS. 3 and 4 , a system and method 50 for tracking articles areshown in which a drawer 20 of the cabinet 40 of FIG. 2 is monitored toobtain data from RFID tags disposed with articles in that drawer. Asmentioned above, a robust field of EM energy needs to be established inthe storage site so that the RFID tags mounted to the various storedarticles will be activated, regardless of their orientation.

In FIGS. 3 and 4 , the tracking system 50 is shown for identifyingarticles in an enclosure and comprises a transmitter 52 of EM energy aspart of an RFID reader. The transmitter 52 has a particular frequency,such as 915 MHz, for transmitting EM energy into a drawer 20 by means ofa transmitting antenna 54. The transmitter 52 is configured to transmitthe necessary RFID EM energy and any necessary timing pulses and datainto the enclosure 20 in which the RFID tags are disposed. In this case,the enclosure is a drawer 20. The computer 44 of an RFID reader 51controls the EM transmitter 52 to cycle between a transmit period and anon-transmit, or off, period. During the transmit period, thetransmitted EM energy at or above a threshold intensity level surroundsthe RFID tags in the drawer thereby activating them. The transmitter 52is then switched to the off period during which the RFID tags respondwith their respective stored data.

The embodiment of FIG. 3 comprises a single transmitting probe antenna54 and a single receiving antenna 56 oriented in such a manner so as tooptimally read the data transmitted by the activated RFID tags locatedinside the drawer 20. The single receiving antenna 56 is communicativelycoupled to the computer 44 of the reader 50 located on the outside ofthe drawer 20 or on the inner bottom of the drawer. Other mountinglocations are possible. Coaxial cables 58 or other suitable signal linkscan be used to couple the receiving antenna 56 to the computer 44. Awireless link may be used in a different embodiment. Although not shownin the figures, those skilled in the art will recognize that variousadditional circuits and devices are used to separate the digital datafrom the RF energy, for use by the computer. Such circuits and deviceshave not been shown in FIGS. 3 and 4 to avoid unneeded complexity in thedrawing.

The embodiment of FIG. 4 is similar to the embodiment of FIG. 3 butinstead uses two transmitting probe antennae 60 and 62 and threereceiving antennae 64, 66, and 68. The configuration and the number oftransmitting probe antennae and receiving antennae to be used for asystem may vary based at least in part on the size of the enclosure 20,the frequency of operation, the relationship between the operationfrequency and the natural resonance frequency of the enclosure, and theexpected number of RFID tags to be placed in it, so that all of the RFIDtags inside the enclosure can be reliably activated and read. Thelocation and number of RFID reader components can be dependent on theparticular application. For example, fewer components may be requiredfor enclosures having a relatively small size, while additionalcomponents, such as shown in FIG. 4 , may be needed for largerenclosures. Although shown in block form in FIGS. 3 and 4 , it should berecognized that each receiving antenna 56, 64, 66, and 68 of the system50 may comprise a sub-array in a different embodiment.

The transmit antennae (54, 60, and 62) and the receive antennae (56, 64,66, and 68) may take different forms. In one embodiment as is discussedin more detail below, a plurality of “patch” or microstrip antennae wereused as the reader receiving antennae and were located at positionsadjacent various portions of the bottom of the drawer while the transmitantennae were wire probes located at positions adjacent portions of thetop of the drawer. It should be noted that in the embodiments of FIGS. 3and 4 , the RFID reader 50 may be permanently mounted in the samecabinet at a strategic position in relation to the drawer 20.

One solution for reliably interrogating densely packed or randomlyoriented RFID tags in an enclosure is to treat the enclosure as aresonant cavity. Establishing a resonance within the cavity enclosurecan result in a robust electromagnetic field capable of activating allRFID tags in the enclosure. This can be performed by building anenclosure out of electrically conductive walls and exciting the metallicenclosure, or cavity, using a probe or probes to excite transverseelectric (TE) or transverse magnetic (TM) fields in the cavity at thenatural frequency of resonance of the cavity. This technique will workif the cavity dimensions can be specifically chosen to set up theresonance at the frequency of operation or if the frequency of operationcan be chosen for the specific enclosure size. Since there are limitedfrequency bands available for use in RFID applications, varying the RFIDfrequency is not an option for many applications. Conversely, requiringa specific set of physical dimensions for the enclosure so that thenatural resonant frequency of the enclosure will equal the availableRFID tag activating frequency will restrict the use of this techniquefor applications where the enclosure needs to be of a specific size.This latter approach is not practical in view of the many differentsizes, shapes, and quantities of medical articles that must be stored.

Referring now to FIG. 5 , a rectangular enclosure 80 is provided thatmay be formed as part of a medical cabinet, such as the cabinet shown inFIG. 2 . It may be embodied as a frame disposed about a non-metallicdrawer in such a cabinet. The enclosure 80 is formed of metallic ormetallized walls 82, floor 83, and ceiling 84 surfaces, all of which areelectrically conductive. All of the walls 82, floor 83, and ceiling 84may also be referred to herein as “walls” of the enclosure. FIG. 5 alsoshows the use of an energy coupling or probe 86 located at the topsurface 84 of the enclosure 80. In this embodiment, the probe takes theform of a capacitor probe 88 in that the probe 88 has a first portion 94that proceeds axially through a hole 90 in the ceiling 84 of theenclosure. The purpose of the coupling is to efficiently transfer theenergy from the source 52 (see FIGS. 3 and 4 ) to the interior 96 of theenclosure 80. The size and the position of the probe are selected foreffective coupling and the probe is placed in a region of maximum fieldintensity. In FIG. 5 , a TE₀₁ mode is established through the use ofcapacitive coupling. The length and distance of the bent portion 94 ofthe probe 88 affects the potential difference between the probe and theenclosure 80.

Similarly, FIG. 6 presents an inductive coupling 110 of the externalenergy to an enclosure 112. The coupling takes the form of a loop probe114 mounted through a side wall 116 of the enclosure. The purpose ofthis probe is to establish a TM₀₁ mode in the enclosure.

The rectangular enclosures 80 and 112 shown in FIGS. 5 and 6 each have anatural frequency of resonance f_(n), shown in FIG. 7 and indicated onthe abscissa axis 118 of the graph by G. This is the frequency at whichthe coupled power in the enclosure is the highest, as shown on theordinate axis 119 of the graph. If the injected energy to the enclosuredoes not match the G frequency, the coupled power will not benefit fromthe resonance phenomenon of the enclosure. In cases where the frequencyof operation cannot be changed, and is other than f_(n), and the size ofthe enclosure cannot be changed to obtain an f_(n) that is equal to theoperating frequency, another power coupling apparatus and method must beused. In accordance with aspects of the invention, an apparatus andmethod are provided to result in a forced resonance f_(f) within theenclosure to obtain a standing wave within the enclosure withconstructive interference. Such a standing wave will establish a robustenergy field within the enclosure strong enough to activate all RFIDtags residing therein.

When an EM wave that is resonant with the enclosure enters, it bouncesback and forth within the enclosure with low loss. As more wave energyenters the enclosure, it combines with and reinforces the standing wave,increasing its intensity (constructive interference). Resonation occursat a specific frequency because the dimensions of the cavity are anintegral multiple of the wavelength at the resonance frequency. In thepresent case where the injected energy is not at the natural resonancefrequency f_(n) of the enclosure, a solution in accordance with aspectsof the invention is to set up a “forced resonance” in an enclosure. Thisforced resonance is different from the natural resonance of theenclosure in that the physical dimensions of the enclosure are not equalto an integral multiple of the wavelength of the excitation energy, asis the case with a resonant cavity. A forced resonance can be achievedby determining a probe position, along with the probe length to allowfor energy to be injected into the cavity such that constructiveinterference results and a standing wave is established. The energyinjected into the enclosure in this case will set up an oscillatoryfield region within the cavity, but will be different from a standingwave that would be present at the natural resonance frequency f_(n) of aresonant cavity. The EM field excited from this forced resonance will bedifferent than the field structure found at the natural resonance of aresonant cavity, but with proper probe placement of a probe, a robust EMfield can nevertheless be established in an enclosure for RFID taginterrogation. Such is shown in FIG. 8 where it will be noted that thecurve for the forced resonance f_(f) coupled power is close to that ofthe natural resonance f_(n).

Turning now to FIG. 9 , an enclosure 120 having two energy injectionprobes is provided. The first probe 86 is capacitively coupled to theenclosure 120 in accordance with FIG. 5 to establish a TE₀₁ mode. Thesecond probe 114 is inductively coupled to the enclosure 120 inaccordance with FIG. 6 to establish a TM₀₁ mode. These two probes areboth coupled to the enclosure to inject energy at a frequency f_(f) thatis other than the natural resonance frequency f_(n) of the enclosure.The placement of these probes in relation to the ceiling 126 and walls128 of the enclosure will result in a forced resonance within theenclosure 120 that optimally couples the energy to the enclosure andestablishes a robust EM field within the enclosure for reading RFID tagsthat may be located therein. The placement of these probes in relationto the walls of the enclosure, in accordance with aspects of theinvention, result in the forced resonance curve f_(f) shown in FIG. 8 .

Referring briefly to FIG. 10 , an impedance matching circuit 121 isshown that functions to match the impedance of a source of energy 122 tothe enclosure 120. The impedance matching circuit is located between thecoaxial cable 122 that feeds activating energy to the enclosure 120 andthe capacitively coupled probe 88 through a hole in the metallic ceiling126 of the enclosure. While the hole is not shown in the drawing of FIG.10 , the insulator 123 that electrically insulates the probe from themetallic ceiling is shown. In this case, the matching circuit 121consists of only a resistive attenuator 124 used to reduce reflectionsof energy by the enclosure 120. However, as will be appreciated by thoseof skill in the art, capacitive and inductive components are likely toexist in the enclosure and in the coupling 88. FIG. 11 on the other handpresents an impedance matching circuit 124 having passive reactivecomponents for use in matching the impedance of the coaxial cable/energysource 122 and the enclosure 120. In this exemplary impedance matchingcircuit 124, an inductive component 125 and a capacitive component 127are connected in series, although other configurations, including theaddition of a resistive component and other connection configurations,are possible.

Passive components such as resistors, inductors, and capacitors shown inFIGS. 10 and 11 can be used to form matching circuits to match theimpedances of the energy source and the enclosure. This will aid incoupling power into the enclosure. However, the passive matching circuitwill improve the impedance match for a specific enclosure loading, suchas an empty enclosure, partially loaded, or fully loaded enclosure. Butas the enclosure contents are varied, the impedance match may not beoptimized due to the variation in contents in the enclosure causing theimpedance properties of the enclosure to change.

This non-optimal impedance match caused by variation in enclosureloading can be overcome by the use of an active impedance matchingcircuit which utilizes a closed loop sensing circuit to monitor forwardand reflected power. Referring now to FIG. 12 , an active matchingcircuit 130 is provided that comprises one or several fixed valuepassive components such as inductors 132, capacitors 134, or resistors(not shown). In addition, one or several variable reactance devices,such as a tunable capacitor 134, are incorporated into the circuit;these tunable devices making this an active impedance matching circuit.The tunable capacitor 134 can take the form of a varactor diode,switched capacitor assembly, MEMS capacitor, or BST (Barium StrontiumTitanate) capacitor. A control voltage is applied to the tunablecapacitor 134 and varied to vary the capacitance provide by the device.The tunable capacitor 134 provides the capability to actively change theimpedance match between the probe 140 and the enclosure 142.

To complete the active matching circuit, a dual directional coupler 144along with two power sensors 146 can be incorporated. The dualdirectional coupler 144 and the power sensors 146 provide the ability tosense forward and reflected power between the RFID transceiver 148 andthe active matching circuit 130 and enclosure 142. Continuous monitoringof the ratio of forward and reflected power by a comparator 150 providesa metric to use to adjust the tunable capacitor 134 to keep the probe140 impedance matched to the enclosure 142. An ability to continuouslymonitor and improve the impedance match as the contents of the enclosureare varied is provided with the active matching circuit 130.

Referring now to the side cross-sectional view of FIG. 13 , twoceiling-mounted 160 probe antennae 162 and 164 are shown mounted withinan enclosure, which may also be referred to herein as a cavity 166,which in this embodiment, operates as a Faraday cage. As shown, theFaraday cage 166 comprises walls (one of which is shown) 168, a back170, a floor 172, a ceiling 160, and a front 161 (only the position ofthe front wall is shown). All surfaces forming the cavity areelectrically conductive, are electrically connected with one another,and are structurally formed to be able to conduct the frequency ofenergy f_(f) injected by the two probes 162 and 164. In this embodiment,the cavity 166 is constructed as a metal frame 167 that may form a partof a medical supply cabinet similar to that shown in FIG. 2 . Into thatmetal frame may be mounted a slidable drawer. The slidable drawer inthis embodiment is formed of electrically inert material, that is, it isnot electrically conductive, except for the front. When the drawer isslid into the cabinet to a closed configuration, the electricallyconductive front panel of the drawer comes into electrical contact withanother part or parts of the metallic frame 167 thereby forming thefront wall 161 of the Faraday cage 167.

The amount of penetration or retention into the cavity by the centralconductor 180 of each probe is selected so as to achieve optimumcoupling. The length of the bent portion 94 of the probe is selected toresult in better impedance matching. The position of the probe inrelation to the walls of the cavity is selected to create a standingwave in the cavity. In this embodiment, the probe antennae 162 and 164have been located at a particular distance D1 and D3 from respectivefront 161 and back 170 walls. These probe antennae, in accordance withone aspect of the invention, are only activated sequentially after theother probe has become inactivated. It has been found that thisconfiguration results in a standing wave where the injected energy wavesare in phase so that constructive interference results.

FIG. 14 is a front perspective view of the probe configuration of FIG.13 again showing the two probe antennae 162 and 164 located in aFaraday-type enclosure 166 for establishing a robust EM field in anarticle storage drawer to be inserted. It should be noted again that theFaraday cavity 166 is constructed as a metallic frame 167. In thisfigure, the cavity is incomplete in that the front surface of the “cage”is missing. In one embodiment, this front surface is provided by anelectrically conductive front panel of a slidable drawer. When thedrawer is slid into the cabinet, the front panel will make electricalcontact with the other portions of the metallic frame 167 therebycompleting the Faraday cage 166, although other portions of the drawerare plastic or are otherwise non-electrically conductive. In theembodiment discussed and shown herein, the two probe antennae 162 and164 are both located along a centerline between the side walls 166 and168 of the frame 166. The enclosure in one embodiment was 19.2 incheswide with the probe antennae spaced 9.6 inches from each side wall. Thiscentered location between the two side walls was for convenience in thecase of one embodiment. The probes may be placed elsewhere in anotherembodiment. In this embodiment, the spacing of the probes 162 and 164from each other is of little significance since they are sequentiallyactivated. Although not shown, two receiving antennae will also beplaced into the Faraday cage 166 to receive response signals from theactivated RFID tags residing within the cavity 166.

It will also be noted from reference to the figures that the probes eachhave a bent portion used for capacitive coupling with the ceiling 160 ofthe cavity, as is shown in FIG. 13 . The front probe 162 is bent forwardwhile the back probe 164 is bent rearward A purpose for thisconfiguration was to obtain more spatial diversity and obtain bettercoverage by the EM field established in the drawer. Other arrangementsmay be possible to achieve a robust field within the cavity 166.Additionally two probes were used in the particular enclosure 166 sothat better EM field coverage of the enclosure 166 would result.

FIG. 15 is a cutaway perspective side view of the dual probe antennae162 and 164 of FIGS. 13 and 14 , also with the drawer removed forclarity. The front probe 162 is spaced from the left side wall by ½ λ ofthe operating frequency F_(f) as shown. It will be noted that the probeseach have a bent portion used for capacitive coupling with the ceiling160 of the enclosure 166 as shown in FIG. 13 . The front probe 162 isbent forward for coupling with the more forward portion of the enclosurewhile the back probe 164 is bent rearward for coupling with the morerearward portion of the enclosure 166 to obtain more spatial diversityand obtain better coverage by the EM field in the drawer. Otherarrangements may be possible to achieve a robust field and furtherspatial diversity and coverage within the enclosure.

FIG. 16 is a frontal upward-looking perspective view of the frame 167forming a Faraday cage 166 showing a portion of a drawer 180 that hasbeen slidably mounted within the frame 167. The front metallic panel ofthe drawer has been removed so that its sliding operation can be moreclearly seen. It will also be noted that the dual ceiling mount probeantennae 162 and 164 have been covered and protected by anelectromagnetically inert protective cover 182. The drawer is formed ofa non-metallic material, such as a plastic or other electromagneticinert material having a low RF constant. The back 184 of the drawer hasalso been cut away so that a cooling system comprising coils 186 and afan 188 located in the back of the frame 167 can be seen. In this case,the drawer 180 is slidably mounted to the Faraday cage frame withmetallic sliding hardware 190. The sliding hardware of the drawer is sonear the side of the frame 167 of the enclosure 166 and may be inelectrical contact with the metallic slide hardware of the side walls168 of the enclosure that these metallic rails will have only a smalleffect on the EM field established within the enclosure.

FIG. 17 is an upward looking, frontal perspective view at the oppositeangle from that of FIG. 16 ; however, the drawer has been removed. Theframe 167 in this embodiment includes a mounting rail 192 for receivingthe slide of the drawer 180. In this embodiment, the mounting rail isformed of a metallic material; however, it is firmly attached to a side168 of the Faraday cage and thus is in electrical continuity with thecage. The figure also shows a spring mechanism 194 used to assist insliding the drawer outward so that access to the articles stored in thedrawer may be gained. The spring is configured to push automatically thedrawer outward when the drawer's latch is released.

FIG. 18 is a schematic view showing measurements of the placement of twoTE₀₁ mode capacitive coupling probes 162 and 164 in the ceiling 160 ofthe frame 167 shown in FIGS. 13-15 . In this embodiment, the frequencyof operation with the RFID tags is 915 MHz, which therefore has awavelength of 0.32764 meters or 1.07494 feet. One-half wavelength istherefore 0.16382 meters or 6.4495 inches. The length of the capacitivecoupling bent portion 200 of each of the probes is 5.08 cm or 2.00 in.The length of the axial extension 202 of the probes into the enclosureis 3.81 cm or 1.50 in., as measured from the insulator 204 into theenclosure 166. The probe configuration and placement in the embodimentwas based on an operation frequency of 915 MHz. In one embodiment, theenclosure 166 had a depth of 16.1 inches (40.89 cm), a width of 19.2inches (48.77 cm), and a height of 3 inches (7.62 cm). It was found thatthe optimum probe placements for this size and shape (rectangular)enclosure and for the 915 MHz operating frequency were: the front probewas spaced from the front wall by 5.0 inches (12.7 cm) and the rearprobe was spaced from the back wall by 5.0 inches (12.7 cm). As discussabove, the probes in this embodiment would only be activatedsequentially.

FIG. 19 is a schematic view of the size and placement within theenclosure 166 of FIG. 16 of two microstrip or “patch” antennae 210 and212 and their microstrip conductors 214 and 216 disposed between therespective antennae and the back of the enclosure at which they will beconnected to SMA connectors (not shown) in one embodiment. Feed lines 58(FIG. 3 ) may be connected to those SMA connectors and routed to thecomputer 44 for use in communicating the RFID signals for furtherprocessing. The measurements of the spacing of some of the microstripcomponents are provided in inches. The spacing of 9.7 in. is equivalentto 24.64 cm. The width of the microstrip line of 0.67 in. is equivalentto 17.0 mm. The spacing of 1.4 in. is equivalent to 3.56 cm. Otherconfigurations and types of receiving antennae may be used, as well asdifferent numbers of such antennae. In the present embodiment, thereceiving antennae are mounted on insulation at the bottom insidesurface of the metallic enclosure frame 167 so that the receiving patchantennae are not in contact with the metal surfaces of the Faraday cage.

Referring now to FIG. 20 , the field intensity or field strength in theenclosure discussed above is shown with the ordinate axis shown involts/meter and the abscissa axis shown in meters. It will be seen fromthe diagram that the maximum field intensity occurs at about 5.0 inches(0.127 m) which results from the probe positioned at 5.0 inches (12.7cm) from the front wall and at a 915 MHz operating frequency. Referringnow to FIG. 21 , the scale has been reduced although the large rise infield intensity can be seen at 5.0 inches. It can also be more clearlyseen that the field intensity falls off at the right wall but remainsstrong very close to the left wall. Therefore in an embodiment, a secondprobe was used that was placed 5.0 inches (12.7 cm) from the right wallthereby resulting in a mirror image field intensity to that shown inFIG. 21 . The two probes 162 and 164 are activated sequentially and arenot both activated simultaneously. It will be noted that better EM fieldcoverage of the enclosure 166 is obtained with the two probes and thatRFID tags on articles positioned close to the front wall 161 will beactivated by the front probe 162 and that RFID tags on articlespositioned close to the rear wall 170 will be activated by the rearprobe 164 (see FIG. 13 ).

Although not intending to be bound by theory, in deriving the probelocation for TE modes in a square or rectangular non-resonant cavity,the following equation can be useful:

$N = {2 \times \frac{L_{2} - L_{1}}{\lambda_{g}}}$

-   -   where:        -   N=positive non-zero integer, for example 1, 2, 3, etc.        -   L₁=distance between probe and back wall        -   L₂=distance between probe and front wall        -   λ_(g)=wavelength in the cavity

L₁ cannot be zero for TE modes, which implies that the probe for TE modeexcitation cannot be at the front or back wall. For TM modes, theequation is the same, but N can equal zero as well as other positiveintegers. The probe position cannot be λ_(g)/2 from the front or backwall. An L₁ and an L₂ are chosen such that N can be a positive integerthat satisfies the equation. For example, for the enclosure 166discussed above:

-   -   L₁=4.785 inches    -   L₂=11.225 inches    -   λ_(g)=12.83 inches

Therefore,

$N = {{2 \times \frac{11.215 - 4.785}{12.83}} = 1.}$

The actual enclosure had the probe located at a slightly differentlocation (5.0 inches) than that indicated by the equation (4.785 inches)which was possibly due to the insertion of a plastic drawer in thecavity, which introduces a change in the phase from the reflectedsignals. The equation above is set up such that the reflected phase fromboth front and back walls is equal, i.e., they are “in phase” at theprobe location.

The wavelength in the enclosure, λ_(g), can be calculated usingwaveguide equations. Equations for a rectangular cavity are shown below.The cutoff frequency is required for this calculation. The equationswill change for a cylindrical cavity or for other shapes.

The cutoff frequency is at the point where g vanishes. Therefore, thecutoff frequency in Hertz is:

$\left( f_{c} \right)_{mn} = {\frac{1}{2\pi\sqrt{\mu\varepsilon}}\sqrt{\left( \frac{m\pi}{a} \right)^{2} + \left( \frac{n\pi}{b} \right)^{2}}({Hz})}$

The cutoff wavelength in meters is:

$\left( \lambda_{c} \right)_{mn} = {\frac{2}{\sqrt{\left( \frac{m}{a} \right)^{2} + \left( \frac{n}{b} \right)^{2}}}(m)}$

-   -   where:        -   a=inside width        -   b=inside height        -   m=number of ½-wavelength variations of fields in the “a”            direction        -   n=number of ½-wavelength variations of fields in the “b”            direction        -   ϵ=permittivity        -   μ=permeability

The mode with the lowest cutoff frequency is called the dominant mode.Since TE₁₀ mode is the minimum possible mode that gives nonzero fieldexpressions for rectangular waveguides, it is the dominant mode of arectangular waveguide with a>b and so the dominant frequency is:

$\left( f_{c} \right)_{10} = {\frac{1}{2a\sqrt{\mu\varepsilon}}({Hz})}$

The wave impedance is defined as the ratio of the transverse electricand magnetic fields. Therefore, impedance is:

$Z_{TE} = {\frac{E_{x}}{H_{y}} = {\frac{{jw}\mu}{\gamma} = {\left. \frac{{jw}\mu}{j\beta}\Rightarrow Z_{TE} \right. = \frac{k\eta}{\beta}}}}$

The guide wavelength is defined as the distance between two equal phaseplanes along the waveguide and it is equal to:

${\lambda_{g} = {{\frac{2\pi}{\beta} > \frac{2\pi}{k}} = {\lambda{where}}}}{{k_{c} = \sqrt{\left( \frac{m\pi}{a} \right)^{2} + \left( \frac{n\pi}{b} \right)^{2}}};{and}}{\beta = \sqrt{k^{2} - k_{c}^{2}}}$

FIGS. 22A and 22B together provide a block electrical and signal diagramfor a multiple-drawer medical cabinet, such as that shown in FIG. 2 . Inthis case, the cabinet has eight drawers 220, shown in both FIGS. 22Aand 22B. Each drawer includes two top antennae, two bottom antennae anda lock with a lock sensor 222 for securing the drawer. Signals to andfrom the antennae of each drawer are fed through an RF multiplexerswitch 224. Each RF multiplexer switch 224 in this embodiment handlesthe routing of RF signals for two drawers. RFID activation field andRFID received signals are fed through the respective RF multiplexerswitch 224 to a main RFID scanner 230 (see FIG. 22B). The scanner 230output is directed to a microprocessor 232 (see FIG. 22B) for use incommunicating relevant information to remote locations, in this case bywired connection 234 and wireless connection 236 (see FIG. 22B). Varioussupport systems are also shown on FIGS. 22A and 22B, such as powerconnections, power distribution, back up battery (see FIG. 22B),interconnection PCBA, USB support (see FIG. 22A), cooling (see FIG.22B), and others.

In accordance with one embodiment, drawers are sequentially monitored.Within each drawer, the antennae are sequentially activated by theassociated multiplexer 224. Other embodiments for the signal andelectrical control systems are possible.

FIG. 25 shows an embodiment of an inventory management system 340according to aspects of the invention. An enclosure 342 is shown, whichin this case creates a Faraday cage in that all the walls and top andbottom are electrically conductive which isolates the enclosure bypreventing (or significantly attenuating) electromagnetic energy fromentering or escaping the enclosure. The enclosure is fitted with areader 344 configured to interrogate RFID tags located within theenclosure, which may take the form of those devices shown in FIG. 1 .The reader 344 is connected to a computer 346 through a connection 348.The connection 348 may be a wired connection, wireless connection, orany other suitable connection for data transfer. In one embodiment, thephysical body of the computing system may be attached to the enclosure342. The computing system 346 has a non-volatile memory 354 in which isstored at least one database (“db”) which may be a local database, orother. The non-volatile memory 354 comprises one or more computerreadable media within the computer system 346 and may be located withinthe computer itself or external to the computer. The memory is shownhere as being outside the computer only for clarity of illustration inthe discussion and is not meant to limit the invention in any way. Inanother embodiment, part or all of the local database may be held on aserver 360. The computing system 346 is also connected to the remotedatabase 360 at which is located a first remote database 362 and asecond remote database 364. As in the local computer, these remotedatabases may be stored on a memory that is internal to the server orthat is external to the server. Further, the server 360 may be locatednearby the local computer 346 or may be remote therefrom. By remote, itis meant that it may be in the same room, or in the same wing, or in thesame facility, or may be in the cloud. Connection 366 to the server 360may likewise be a wired connection, wireless connection, or any othersuitable connection for data transfer.

In one embodiment, the data held on the local database 352 may depend onthe location/specialty/facility using computer system 346. For example,if the computer system 346 were stationed in an emergency room (“ER”),the local database 352 may hold only information or data regardingmedical articles, medical containers, and other inventory most used inan ER. In one embodiment, the remote database 362 at the server 360 mayserve as a main database and contain data for all medical articles,medical containers, and other inventory for all medicallocations/facilities/specialties. The local database 352 may maintain acopy of the portion of data held on the remote database 362 that is mostrelevant to the computer system 346, but can access the remote database362 when encountering medical items, medical containers, or otherinventory for different facilities/specialties/locations.

The enclosure 342 has an opening 370 through which a tray 372 may beslid into the enclosure. The tray is placed completely within theenclosure so that the front door 374 can be closed over the opening 370to complete the Faraday cage of the enclosure 342. The tray includes anumber of medical items 376 with each one having an RFID tag 378attached. As discussed previously, each RFID tag has a stored differentidentification number comprising a few bytes with a check digit.Manufacturers guarantee that each serial number is used only once. SomeRFID tags have more complex codes for identifying the RFID tag. In thiscase, the tray 372 also has an RFID tag 280 attached to its outersurface 382. The reader 344 will read those identification numbers fromthe tags, communicate them to the computer which will compare themagainst one or more databases either locally 352 or remotely through aserver 362 and/or 364. The process of using the identification numbersof the tags is discussed below.

Medical item information may include information such as name, lot code,date of manufacture, expiration date, dosage, weight, color, and animage of the medical article. In one embodiment, the identification(“ID”) data may be partially made of drug codes that identify the drugs.As an example and not by way of limitation, the identification data mayuse the National Drug Code (“NDC”) as part of its data allowing for easyidentification of the attached medical item. Identification data mayalso have other identifying codes that establish the manufacturer, lotcode, dosage, drug type, expiration date, etc.

Shown in FIG. 26 is an enclosure 342 formed in accordance with aspectsof the invention by which it is much smaller than an enclosure sized tobe resonant at the operating frequency of RFID yet the EM field withinthe enclosure 342 is highly robust and effective at exciting and readingall RFID tags located therein. Because inventive aspects areincorporated, the enclosure is much smaller than other enclosures and istherefore highly desirable in areas where space is limited, such as apharmacy in a healthcare facility. Although not shown, the front door374 includes latching hardware to retain it in a closed when it isrotated upwards and put in use. A handle 384 assists in managing theconfiguration of the front door. The enclosure is formed of a metallicmesh or solid metallic material to establish a Faraday cage about traysthat are slid within it for scanning and inventorying. The front door inthis embodiment is also formed of a metallic material and closes theFaraday cage when the door 374 is closed. The RFID reader 344 is shownin dashed lines as are the electronics and battery 388 for theenclosure. The electronics include a processor, communications, wiredand wireless connections, and a local power source. In anotherembodiment, an AC adapter may be included for using wall power.Communications ability over networks is provided.

The approximate volume for a resonant enclosure at an RFID operatingfrequency of 900 MHz is 3 ft.×3 ft.×3 ft. for a total of 27 cubic feet.In one embodiment, the enclosure 342 had the dimensions of 2.25 ft. wideby 1.6 ft. long by 0.88 ft. high for an approximate volume of 3.15 cubicfeet, yet achieved an equally effective EM field within the enclosure atexciting and reading all RFID tags located therein. The difference insizes of the two enclosures makes one formed in accordance with theinvention more attractive in many situations where space is limited.

FIG. 27 presents another enclosure 390 of a much larger size so that itcan accommodate crash carts 392 that do not include an internal RFIDreader. In this embodiment, enclosure 390 has a ceiling 394 and a floor396 which are at least partially metallic. The enclosure 390 also hastwo fixed side walls 398 and 400 and a back (not shown). Part of an RFIDreader system 402 is shown within the enclosure. The front part 404 ofthe enclosure is a hinged metallic door that, when closed, completes theFaraday cage of the enclosure 390. Instead of a door, the front 404 maybe a flexible panel that is also at least partially metallic. Otherapproaches to providing a covering over the front opening are possible,provided that they complete the Faraday cage about the crash cart 392once it is moved completely within the enclosure 390. In an alternativeembodiment, all four sides of the enclosure may be made of flexiblepanels so that the enclosure can more easily be moved to anotherlocation. In one embodiment, the ceiling, floor, sides, back, and frontcan all be fitted with RFID readers/antennas 402 so that articles withinthe crash cart having RFID tags can be accurately identified.

It should be noted that use of a Faraday cage is highly beneficial inhealthcare facilities due to the ubiquitous presence of medical articlesthat have RFID tags. Without the ability to electrically isolate thetray or crash cart to be read, an RFID reader may read the RFID tags ofother pharmaceuticals on shelves outside the tray or crash cart therebygiving the operator the incorrect information that those external readarticles are in the tray or crash cart.

The enclosure of FIG. 27 includes a ramp 406 that may or may not beattached to the floor 396 of the enclosure. The purpose of the ramp isto facilitate rolling the crash cart into the enclosure. Other means arepossible.

FIG. 28 is a schematic diagram depicting an exemplary implementation ofan inventory management system 410 according to an embodiment of theinvention. Starting at the top, a database of medical articles managedby the system 410 is built 411. As an example, a medication vial 412 onwhich an RFID tag 414 is mounted is being registered with the system 410by entering the RFID tag's serial number 416 along with the relevantinformation 418 about the medication in the vial 412 into an “articlesdatabase” 420 by the computer 422. In this case, the computer comprisesa processor 424, a display 426, and an input device 428 which in thiscase is a keyboard. An RFID reader 430 obtains the RFID tag's serialnumber and assigns it to the medication information in the medication towhich the RFID tag is mounted. In this case, the information about themedication comprises: the drug name, the dose, the volume, theexpiration date, the manufacturer's name, the lot number, the NDCnumber, the UPC number, the tray number in which the medication will bestore, and the location of the medication in the tray. Other informationmay also be included. This is then stored in the Articles Database or“Articles db” 420. Building the Articles database can be done indifferent ways and may be automated or may be pre-prepared by themedication manufacturer and given to the healthcare facility inelectronic form. The above is repeated for all medications and othermedical articles that may be placed in a tray.

The tray database, or “tray db” is built 440 in similar fashion. A tray442 is supplied with its contents according to a Required Inventorylist. Medical articles are collected and properly placed within the tray442. In FIG. 27 , only a few medical articles are shown for the purposeof clarity of the illustration. Many more articles may be placed in thetray. Each medical article within the tray includes an RFID tag 444. Thefully supplied tray is placed within a Faraday cage 446, although thisis not required if the tray can be sufficiently isolated from randomtags, and a reader 448 reads the contents of the tray. The reader alsoreads an RFID tag 449 attached to the tray 442 itself. A computer 450receives the read tag numbers and stores them as a tray database 452. Inthe tray database, the tray RFID tag identification is connected withthe type and name of the tray and the RFID tag numbers are connectedwith the medical articles placed in the tray. Trays may have certaincategories, such as ER, or ICU, or pediatric, or other, and the traydatabase will indicate that category for the RFID no. of the tray RFIDtag. As in the other systems, the computer here includes a processor454, a display 456, and an input device 458 which in this case is akeyboard. The computer also comprises both random access memory andnon-volatile memory, as do the other computers shown and describedherein. In one embodiment, the tray database is relational in that itpoints to the medical articles database to obtain more detailedinformation about its inventory.

While the embodiment herein described refer to “trays,” other containertypes may function equally well. It is not meant to confine theinvention to any particular type of container unless so indicated.

A scanning and inventory system is shown at the bottom of FIG. 28 andincludes positioning the tray to be inventoried 460 within a RFID readerenclosure 446 that provides a Faraday cage within itself. The tray to beinventoried 460 is positioned entirely within the Faraday case part ofthe enclosure 446 so that no external RFID tags will be read by thereader. 462. After closing the enclosure, the RFID reader 462 scans thetray 460, including the RFID tag on the tray itself 490 and the tags oneach of the medical articles within the tray. The identification numbersof each of the read RFID tags is communicated by the reader to acomputer 464 similar to the other computers 424 and 450 described above.The computer includes a display 466, an input device 468 which, in thiscase, is a keyboard, and a processor 470 forming part of the computer464. In this embodiment, the computer processor 470 compares the trayRFID tag serial no. to those stored in the tray database 452. If foundin the tray database, that tray's inventory will be provided for furtherprocessing, as described below.

In accordance with an aspect of the invention, the enclosure describedabove; i.e., enclosure 446, is a RFID scanning enclosure (see FIG. 26 )configured with the robust EM field in accordance with the inventiveaspects above. In particular, the enclosure may be configured as shownin FIGS. 13-17 and perform as described to achieve the robust field fordetecting, activating, and reading all RFID tags within the enclosure.

Referring now to FIG. 29 , a flow chart is provided that describes anembodiment of a method of scanning and inventorying a code tray inaccordance with aspects of the invention. A tray is positioned in anenclosure 490 such as that provided by FIGS. 13-17 and 26 . An RFIDreader then reads the RFID tag of the tray 492. The serial number of thetray RFID tag is then automatically compared to a tray database todetermine if this scanned tray is in the database 494. If the tray isnot in the database, an alarm is provided 496. If the tray is in thetray database, all RFID tags of medical articles in the tray are read,and the names and details of the medical article to which they areattached are automatically compared 498 to the Required Inventory listof that tray. A determination is made if there are any extra articles inthe tray that are not included in the stored tray database 450. Theaccess by the program of multiple databases may be needed to performthis step. If extras are detected, an alarm is provided 496 so thatthose extra articles may be removed from the tray. If no extra articlesare found, a determination is made if all required inventory articlesare in the tray 452. If articles are missing, a list of the missingarticles is automatically displayed 504 and may be printed as needed. Inone feature of an embodiment, the computer program performing the abovesteps may display 506 a graphical image of the tray 506 and indicatewhere in the tray the missing articles should be placed. Such an imageis shown in FIG. 31 where a blinking asterisk 508 indicates where amedical article should be placed. Many different ways may be employed toassist in the placement of medical articles in the tray. Replacementsfor the missing medical articles are collected and the tray isre-supplied 532 by positioning the medical articles at the properlocation in the tray.

If all articles are present in the tray, the computer program may beinformed of such and formalities are then conducted. The electronicrecord for the particular tray is updated and an inventory sheet for thetray is printed for inclusion with the tray. The tray is then sealed andtaken to the assigned location in the healthcare facility for possiblefuture use. However, in the event that the operator of the computerprogram performing the described scanning and inventory, the expirationdates of all medical articles in the tray may be checked. From the scanof the medical articles, the inventory dates are compared against thepresent date 510. In another aspect of the invention, the program maydisplay a screen asking the operator which time period of expiration isdesired for checking. Turning now to FIG. 30 , a screen shot 550 of theprogram is reproduced showing that in this embodiment, a drop-down list552 of expiration periods is available to the operator. By selecting anyone of the periods, the program will then search for and list 554 belowthe selected period all medical items expiring in that time period. Ifany medical items are listed 554, they may be found in the tray andreplaced 514.

The program next proceeds to determining if any scanned medical articleshave been recalled 514 by the manufacturer or the FDA, or otherwise. Thecomparison of the identification of the detected medical articles in thetray are compared to a “Recalled” database and if any articles matchrecalled articles, it is then determined if a substitute medical articleexists 520. If none exists, an alarm is provided 522. If a substitutearticle does exist, a substitute is located 528 and supplied to the tray532. If no recalled articles exist in the tray, in this embodiment, theinventory of the tray is updated in the database 524; i.e., that a scanand verification of contents was just made, an inventory sheet isprinted, and the tray is sealed 526. The tray may now be moved to alocation in the healthcare facility where it may be put to use.

However, in the case above where medical articles had to be added to thetray for missing, expired, or recalled items, a rescan if performed 530in this embodiment. Such scans, rescans, replacements, expiration, andrecalls are all noted for one or more databases kept by the inventoryre-supply system in accordance with the invention. Because of the datacaptured in scans and in the databases built by embodiments, manysearches for medical articles may be performed. For example, if apharmacy were concerned to locate all medications or other medicalarticles having an expiration date within one month (see FIG. 30 ), asearch of one or more databases of the embodiment above can be made tofind such expiring articles. Another search on a database may be thenmade to track the position of those expiring articles; i.e., todetermine if they are in a tray, and if so, which tray it is, and inwhat pocket of the tray. Such trays with expiring articles may begathered, and the re-supply may be made.

Referring now to FIG. 32 , there is shown a computer program screen shot540 of a listing of the articles detected in a tray during a scan ofthat tray in accordance with aspects of the invention. Variouscategories are shown including expiration 542 and recall 544. Incorrectarticles 546 may be listed and for convenience, the entire RequiredInventory list can be displayed as well as a check mark next to each onethat is present and not expired. Many different forms of the display ofresults from scanning a tray, crash cart, or other container may beprovided. FIG. 32 is just one embodiment.

Multiple databases may be employed in the system and method describedabove. According to one embodiment, the system 340 (FIG. 25 ) and themethod 489 (FIG. 29 ) may search one or more databases of medicalarticle information matching the identification data. In one embodimentthe identification data may be found in multiple databases each databasecontaining different information. As by way of example and notlimitation, the name, dosage, lot code and expiration date may be on onedatabase while recall status may be in another database. In anotherembodiment all the medical item information may be held in one databasewhich may have its information on other databases as backup. In yetanother embodiment, medical item information may be stored on a localdatabase within the computing device connected to the enclosure, and thelocal database may be updated periodically over a network connectionfrom one or more remote databases.

The alarms that are provided may be done so visually, such as bydisplayed on a computer screen, audibly, such as through speaker sounds,and/or tactile by vibrations. Other means or combinations of means forcommunicating an alarm condition may be used.

According to one embodiment, the data files within the databasescontaining medical information may take the form of a comma separatedvalue list which may have multiple data fields and may look like “Name,Dosage, and Expiration.” Other serialized formats may be used to containthe data, including but not limited to, Extensible Markup Language(XML), JavaScript Object Notation (JSON), etc. The data may also takethe form of proprietary file formats created by medical articlemanufacturers. Furthermore, the data may contain a pointer or addressesto additional data providing additional information about the medicalitem or medical container. One example of additional information may bea data representation of a medical item's image. There are manydifferent file or data formats that may be used to store medicalinformation and any suitable format is contemplated within thisinvention. In one embodiment, multiple datasets using different dataformats containing medical item information may be used, each for aparticular medical item manufacturer or distributor. A system may beconfigured to identify particular datasets based on the identificationdata from a data carrier (such as an RFID tag). In an alternativeembodiment, a single data format may be used across all medical itemsindependent of manufacturers.

The inventory management system in accordance with the invention maydisplay a list of every medical item missing from the medical container,any additional medical items not within the inventory list, any drugswith incorrect dosages, and any expiration date and/or status of everymedical item within the container that is attached to a data carrierwith identification data. In one embodiment as discussed above, thesystem may also display an image of each medical article that ismissing, additional, incorrect dosage, expired, recalled, etc. Thatimage of the medical article may make it easier for operators to findthe displayed medical article or articles in the medical container. Theimage may be a visual representation of the medical article or itscontainer which may include label colors. In an alternative embodiment,a diagram of the medical container may be provided, and the location ofthe medical article in the medical container may be highlighted in thediagram.

In one embodiment, an inventory management system and method inaccordance with the invention may use color indicators to communicateany differences/anomalies with the articles within the medical containerand the inventory list. The inventory management system and method mayalso provide expiration indicators. As an example, but not by way oflimitation, expiration indicators may include displaying a countdown ofthe number of days left until expiration of a medical article. Inanother embodiment, a color indicator using color gradients or colorcoding may indicate the life of the medical article such as green tored, white to black, etc. Each end of the color/gradient spectrum mayrepresent the life or expiration of the a medical article.

In further regard to FIG. 32 , the display may use multiple windows.Each window may display different information regarding the contents ofthe scanned medical container such as a window for missing articles, awindow for expired articles, a window for incorrect or additionalarticles not part of the container's inventory, a window for aninventory list, a window for recalled articles, and a window foraggregated information. Each window may have an image display, name,dosage, number of articles, and expiration or recall status indicator.Each window may also have a scroll bar for additional data that does notfit in a single window. In an alternative embodiment, a single windowmay be used and the user may be provided with the ability to select whatis displayed in the window.

In one embodiment, the inventory management system may allow forregistering or creating specialized and/or individualized medicalcontainers and inventories for entry into one or more databases. A usermay fill a medical container with the correct number of medical articles(attached with data carriers) intended for the medical container. Theuser may insert the medical container into the enclosure of theinventory management system, such as described above in FIG. 28 atnumeral 41. A user may instruct the inventory management system 410through an input device 428, to register the container under a certaincategory, including specialized and/or individualized categories. Thesystem may read identification data from every data carrier within theenclosure. In one embodiment, a data carrier is attached to the medicalcontainer itself. The system 410 may search a database for medicalinformation associated with each identification data read from the datacarriers within the container. The system builds an inventory list fromthe accessed medical article information and stores it on the databasein association with the identification data of the specialized medicalcontainer.

The computers 422, 450 and 464 of FIG. 28 may take any suitable form,including but not limited to, an embedded computer system, asystem-on-chip (SOC), a single-board computer system (SBC) (such as, forexample, a computer-on-module (COM) or system-on-module (SOM)), a laptopor notebook computer system, a smart phone, a personal digital assistant(PDA), a server, a tablet computer system, a kiosk, a terminal, amainframe, a mesh of computer systems, etc. The computers may be acombination of multiple forms. The computers may include one or morecomputer systems, be unitary or distributed, span multiple locations,span multiple systems, or reside in a cloud (which may include one ormore cloud components in one or more networks).

In one embodiment, the computers 422, 450 and 464 of FIG. 28 may includeone or more processors, memory, storage, an input/output (I/O) interface3004, a communication interface, and a bus. Although this disclosuredescribes and illustrates a particular computer system having aparticular number of particular components in a particular arrangements,this disclosure contemplates other forms of computer systems having anysuitable number of components in any suitable arrangement.

In one embodiment, processor includes hardware for executinginstructions, such as those making up software. Herein, reference tosoftware may encompass one or more applications, byte code, one or morecomputer programs, one or more executable, one or more instructions,logic, machine code, one or more scripts, or source code, and viceversa, where appropriate. As an example and not by way of limitation, toexecute instructions, processor may retrieve the instructions from aninternal register, an internal cache, memory or storage; decode anexecute them; and then write one or more results to an internalregister, an internal cache, memory, or storage. In one embodiment,processor may include one or more internal caches for data,instructions, or addresses. Memory may be random access memory (RAM),static RAM, dynamic RAM or any other suitable memory. Storage maybe ahard drive, a floppy disk drive, flash memory, an optical disk, magnetictape, or any other form of storage device that can store data (includinginstructions for execution by a processor).

In one embodiment, storage may be mass storage for data or instructionswhich may include, but not limited to, a HDD, solid state drive, diskdrive, flash memory, optical disc (such as a DVD, CD, Blu-ray, and thelike), magneto optical disc, magnetic tape, or any other hardware devicewhich stores may store computer readable media, data and/or combinationsthereof. Storage may be internal or external to computer system.

The term “operationally responsive” is used herein for the purpose ofadditional clarity. It is believed that one skilled in the art wouldrecognize that an RFID device built for operation at a particularnominal frequency would not be considered operationally responsive at amuch different frequency, even though it may function somewhat, but atan unacceptable or “nonoperational” level. Therefore the term “notresponsive” should be sufficient but for the avoidance of doubt,applicant has used the term not operationally responsive, but believesthat it is synonymous with not responsive.

In one embodiment, input/output (I/O) interface, includes hardware,software, or both for providing one or more interfaces for communicationbetween computer system and one or more I/O devices. Computer systemsmay have one or more of these I/O devices, where appropriate. As anexample but not by way of limitation, an I/O device may include one ormore mouses, keyboards, keypads, cameras, microphones, monitors,display, printers, scanners, speakers, cameras, touch screens,trackball, trackpad, biometric input device or sensor, or the like.

In still another embodiment, a communication interface includeshardware, software, or both providing one or more interfaces forcommunication between one or more computer systems or one or morenetworks. A communication interface may include a network interfacecontroller (NIC) or a network adapter for communicating with an Ethernetor other wired-based network or a wireless NIC or wireless adapter forcommunications with a wireless network, such as a local wirelessnetwork. In one embodiment, bus includes any hardware, software, or bothcoupling components of a computer system to each other.

“Medical article” is used in this document its broadest sense. Forexample, a medical article can be a medical device, a pharmaceuticaldrug, a lab specimen, a blood product, a human organ, a hospital scrub,a surgical instrument, a medical implant, a sponge or gauze pad, ahealthcare institution code tray containing drugs to be tracked, and acode tray containing medical devices to be tracked.

As has been described, the various embodiments of the present inventionrelates to a system and method for medical article inventory andmanagement. For purposes of explanation, specific nomenclature is setforth to provide a thorough understanding of the present invention.Description of specific applications and methods are provided only asexamples. Various modifications to the embodiments will be readilyapparent to those skilled in the art and the general principles definedherein may be applied to other embodiments and applications withoutdeparting from the spirit and scope of the invention. Thus the presentinvention is not intended to be limited to the embodiments shown, but isto be accorded the widest scope consistent with the principles and stepsdisclosed herein.

Although RFID tags are used herein as an embodiment, other data carriersthat communicate through electromagnetic energy may also be usable.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiments,it is to be understood that the invention is not to be limited to thedisclosed embodiments and elements, but, to the contrary, is intended tocover various modifications, combinations of features, equivalentarrangements, and equivalent elements included within the spirit andscope of the appended claims.

Unless the context requires otherwise, throughout the specification andclaims that follow, the word “comprise” and variations thereof, such as,“comprises” and “comprising” are to be construed in an open, inclusivesense, which is as “including, but not limited to.”

While particular embodiments of the present invention have beendescribed, it is understood that various different modifications withinthe scope and spirit of the invention are possible. The invention islimited only by the scope of the appended claims.

1-6. (canceled)
 7. A medical storage container supply system for readingan identification device that is attached to a medical storage containerand for reading identification devices attached to medical articleslocated in the medical storage container to manage the inventory of thestorage container, each of the identification devices being responsiveto electromagnetic (EM) energy to provide identification data, thesystem comprising: an enclosure having an internal storage area, theenclosure further having electrically conductive walls that surround theinternal storage area and a storage container in which medical articlesare located, each medical article having an associated identificationdevice; a probe disposed within the enclosure, the probe configured toinject EM energy into the enclosure; a medical storage container havingan identification device identifying the medical storage container, thestorage container being located within the internal storage area of theenclosure and containing medical articles, each of which having anassociated identification device identifying that medical article, theidentification devices being responsive to EM energy to provideidentification data; wherein the probe is further configured to receiveidentification data provided by identification devices of the medicalstorage container and the medical articles stored in the medical storagecontainer when they are located in the enclosure; an electronic requiredinventory list having a required inventory of medical articles to belocated in the medical storage container; a non-volatile memory on whichis stored the electronic required inventory list of the medical storagecontainer; and a processor programmed to receive the identification dataprovided by the identification device of the medical storage container,to access the non-volatile memory to locate the electronic requiredinventory list of the identified medical storage container, to receiveidentification data provided by the identification devices of themedical articles located in the storage container in the enclosure, andto compare the received identifications of medical articles to therequired inventory list of required medical articles for the medicalstorage container to determine from the comparison at least one ofwhether there are missing medical articles not in the medical storagecontainer that are on the required inventory list, and whether there areextra medical articles in the medical storage container but not on therequired inventory list.
 8. The medical storage container supply systemof claim 7 further comprising a display, and wherein the processor isfurther programmed to control the display to display a list of missingmedical articles.
 9. The medical storage container supply system ofclaim 7 further comprising a display, and wherein the processor isfurther programmed to control the display to display a diagram of theidentified medical storage container to highlight locations on thediagram where missing medical articles should have been located.
 10. Themedical storage container supply system of claim 7 further comprising adisplay, and wherein the processor is further programmed to control thedisplay to display the inventory list on the display with marks on thedisplayed inventory list indicating what medical articles were found tobe present in the medical storage container.
 11. The medical storagecontainer supply system of claim 7 further comprising a display, andwherein the processor is further programmed to control the display todisplay graphical images of missing medical articles.
 12. The medicalstorage container supply system of claim 7 further comprising a display,and wherein: the non-volatile memory also comprises a database ofdiagrams showing locations where medical articles are to be located inthe medical storage container; the processor is further programmed suchthat if the processor determines that medical articles are missing froman identified medical storage container, the processor accesses thedatabase of diagrams of the locations of medical articles in the medicalstorage container; and the processor controls the display to display adiagram of the location in the medical storage container in which themissing medical articles should be placed.
 13. The medical storagecontainer supply system of claim 7 wherein if the identification data ofthe medical storage container is not found in the database on thenon-volatile memory, the processor is programmed to provide an alarm.14. The medical storage container supply system of claim 7 furthercomprising a display, and wherein the processor is further programmed tocontrol a display to display multiple windows of data about the contentsof an identified medical storage container wherein each window displaysdifferent information regarding the contents of the identified medicalstorage container, including at least one of: a window for missingmedical articles; a window for extra or additional or incorrect medicalarticles not part of the storage medical container's inventory list; awindow for an inventory list; and a window for aggregated information.15. The medical storage container supply system of claim 7 wherein theenclosure includes an opening having a size large enough so that amedical storage container presently located in the internal storage areaof the enclosure can be removed from the enclosure and a differentmedical storage container can be placed in the internal storage area ofthe enclosure in place of the one removed.
 16. A method of supplying amedical storage container by reading an identification device that isattached to the medical storage container and for reading identificationdevices attached to medical articles located in the medical storagecontainer to manage the inventory of the medical storage container, eachof the identification devices being responsive to electromagnetic (EM)energy in response to which the identification devices provideidentification data, the medical storage container and medical articlesbeing located within an internal storage area of an enclosure, theenclosure having electrically conductive walls that surround theinternal storage area and a medical storage container holding medicalarticles with associated identification devices placed therein, themethod comprising: positioning a medical storage container within theinternal storage area of the enclosure, the storage container having anidentification device identifying the storage container, the medicalstorage container containing medical articles, wherein each of themedical articles located therein having an associated identificationdevice, the identification devices being responsive to electromagnetic(EM) energy to transmit identification data; injecting EM energy intothe enclosure from a location within the enclosure; storing anelectronic inventory list of the medical storage container on anon-volatile memory; receiving the identification data of the medicalstorage container by a processor, locating the inventory list of theidentified medical storage container in the non-volatile memory by theprocessor through the identification of the medical storage container,receiving identification data of the medical articles located in themedical storage container, locating the details of the medical articlesin the identified medical storage container by the processor in thenon-volatile memory through the identification data of the medicalarticles, comparing the details of the identified medical articlesagainst the inventory list of the medical storage container in which theidentified medical articles are located, and based on the step ofcomparing, determining at least one of whether there are missing medicalarticles not in the medical storage container that are on the inventorylist, and whether there are extra medical articles in the medicalstorage container that are not on the inventory list for the container.17. The method of supplying a medical storage container of claim 16wherein if it is determined that there are missing medical articles fromthe identified medical storage container, then controlling a display todisplay a list of the missing medical articles.
 18. The method ofsupplying a medical storage container of claim 16 wherein if an extramedical article is detected, providing an alarm whereby the extraarticle may be removed from the medical storage container.
 19. Themethod of supplying a medical storage container of claim 16 furthercomprising controlling a display to display graphical images of missingmedical articles.
 20. The method of supplying a medical storagecontainer of claim 16 wherein if it is determined that medical articlesare missing from the identified medical storage container, thendisplaying a diagram of the location in the medical storage container inwhich the missing medical articles should be located.
 21. The method ofsupplying a medical storage container of claim 16 wherein whenidentification data of the identified medical storage container and theidentification data of the identified medical articles in the medicalstorage container are received, displaying a list with marks on the listindicating what medical articles were found to be present in the medicalstorage container.
 22. The method of supplying a medical storagecontainer of claim 16 further comprising displaying multiple windows ofdata about the contents of an identified medical storage containerwherein each window displays different information regarding thecontents of the identified medical storage container, including at leastone of: a window for missing medical articles; a window for extra,incorrect, or additional medical articles not part of the medicalstorage container's inventory list; a window for a required inventorylist; and a window for aggregated information.
 23. The method ofsupplying a medical storage container of claim 16 further comprisingdisplaying a diagram of the medical storage container and highlightingthe locations of missing medical articles in the medical storagecontainer in the diagram.
 24. The method of supplying a medical storagecontainer of claim 16 wherein if the identification data of the medicalstorage container is not found in the database on the memory, providingan alarm.
 25. The method of supplying a medical storage container ofclaim 16 further comprising removing a medical storage containerpresently located in the internal storage area of the enclosure throughan opening in the enclosure and replacing the removed medical storagecontainer with a different medical storage container.
 26. A medicalstorage container supply system for reading an identification devicethat is attached to a medical storage container and for readingidentification devices attached to medical articles located in themedical storage container to manage the inventory of the storagecontainer, each of the identification devices being responsive toelectromagnetic (EM) energy to provide identification data, the systemcomprising: an enclosure having an internal storage area, the enclosurefurther having electrically conductive walls that surround the internalstorage area and a storage container in which medical articles arelocated, and also having an opening through which a storage containerlocated in the internal storage area can be replaced with a differentstorage container, each medical article having an associatedidentification device; a probe disposed within the enclosure, the probeconfigured to inject EM energy into the enclosure; a medical storagecontainer having an identification device identifying the medicalstorage container, the storage container being located within theinternal storage area of the enclosure and containing medical articles,each of which having an associated identification device identifyingthat medical article, the identification devices being responsive to EMenergy to provide identification data; wherein the probe is furtherconfigured to receive identification data provided by identificationdevices of the medical storage container and the medical articles storedin the medical storage container when they are located in the enclosure;an electronic required inventory list having a required inventory ofmedical articles to be located in the medical storage container; anon-volatile memory on which is stored the electronic required inventorylist of the medical storage container; a display; and a processorprogrammed to receive the identification data provided by theidentification device of the medical storage container, to access thenon-volatile memory to locate the electronic required inventory list ofthe identified medical storage container, to receive identification dataprovided by the identification devices of the medical articles locatedin the storage container in the enclosure, and to compare the receivedidentifications of medical articles to the required inventory list ofrequired medical articles for the medical storage container to determinefrom the comparison at least one of whether there are missing medicalarticles not in the medical storage container that are on the requiredinventory list, and whether there are extra medical articles in themedical storage container but not on the required inventory list;wherein the processor is further programmed to control the display todisplay the inventory list on the display with marks on the displayedinventory list indicating either what medical articles were found to bepresent in the medical storage container, or what medical articles werefound to be missing in the medical storage container.